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 wealth of information on the physical properties
and global distribution of clouds soon to be collected by a recently
launched satellite called Terra could help scientists better
predict climate change, says a University of Illinois researcher
involved with the project.
 "Terra
is the flagship of NASA's Earth Observing System Program, an
international effort to monitor Earth's climate over the next
15 years," said Larry Di Girolamo, a professor of atmospheric
sciences. "During the satellite's six-year lifetime, its
five instruments will help scientists understand how clouds,
aerosols, air pollutants, oceans, vegetation and ice cover interact
with each other and impact the climate we live in."
Di Girolamo's
research focuses on clouds. "From a climate-modeling perspective,
clouds contribute the largest uncertainty to climate change,"
he said. "Clouds may have a warming or cooling effect on
the planet, depending on the cloud properties. Because clouds
are so variable, their effect on global climate has been difficult
to quantify."
One of the
instruments on Terra is the Multi-angle Imaging Spectro-Radiometer.
MISR will be the first instrument to make global, high-resolution,
multi-angle, multispectral radiometric measurements of Earth
from space. The instrument will characterize cloud, aerosol and
surface properties in a manner no other satellite has been capable
of.
"It's
MISR's ability to look at the same scene from different angles
at a high resolution that makes MISR so unique," Di Girolamo
said. "You get a lot more information about an object when
you look at it from different angles than you do when you look
at it from a single angle."
Unlike traditional
meteorological satellites that have only one camera, MISR has
nine cameras that will successively view portions of the planet
in four spectral bands. "By combining spectral and angular
signatures, we can gather more information about atmospheric
or surface features than spectral signatures alone," Di
Girolamo said. "The use of multiple cameras also permits
stereoscopic imaging, allowing us to look at clouds in 3-D."
Di Girolamo
has been involved with the MISR project for the past decade.
As a graduate student, he worked on new techniques for studying
clouds from multi-angle data, which helped set the instrument
specifications. More recently, he developed the cloud-detection
and classification algorithms that will process the complex data
needed to better understand the role that clouds play in Earth's
climate system.
Lofted into
orbit on Dec. 18, the Terra instruments are being rigorously
tested prior to measurements of scientific data. For more information
on the Terra and MISR missions, visit http://terra.nasa.gov,
a Web page maintained by the National Aeronautics and Space Administration.
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